The first settlers of Sri Lanka (Indo-Aryan) possessed a high technical ability, with wide vision and a highly developed “water” and topographical sense. The vastness of conception of the irrigation system of ancient Sri Lanka removes all doubt that the old engineer must have depended to a critical degree on a system of levelling

Dating back to the 1st century BCE, Anicut, Vaan, and Bisokotuwa invented by ancient Sri Lankan engineers are comparable to the modern sluice, spillway and valve pits.

The culture of Sri Lanka is generally described as Sinhala Buddhist culture. Even though there are three other minor cultures that originated in the latter period. Other minority cultures on the island are identified as Tamil Hindu Culture, Christian Culture, and Muslim Culture. Sinhalese are the dominating ethnic group on the island while Buddhism is the most widely practised religion in Sri Lanka.

Sinhala Buddhist culture flourished in agriculture and they invented a sophisticated irrigation system to get water to their fields. This irrigation system can still be seen in the central province of Sri Lanka and they are still serving the people. Ancient Sri Lankans strictly adhere to their religion, which was Buddhism. When you tour the cultural triangle of Sri Lanka to witness the ancient temples, stupas, ad palaces such as Sigiriya rock, Polonnaruwa you will encounter a large number of tanks, lakes and canals. Most of those tanks and canals originated along with the ancient constructions in the region.

These two dominating factors (Sinhala and Buddhist) have created a separate identity for the country and its culture. These two factors have evolved together for the last two and half millenniums, they are interdependent and inseparable. Due to their influence, today the religion and culture of the country are known as Sinhala Buddhist or Sinhala Buddhism.

Sinhalese is considered to be the first ethnic group that established a settlement on the island. These migrants came from North Indian Aryavarta, hence they belonged to Aryan stock.

Ancient Settlements

Historian is of the opinion that they could be a band of the seafaring merchant, who sailed southward direction searching for a destination with luxurious merchandise such as gems, pearls etc, which had a ready demand from the upper strata of the Aryavarta society.

It is believed they settled in Sri Lanka, due to the tradition of creating new colonies in the countries they reach. According to the Sinhalavatthu, an ancient Pali chronicle that originated in the 3^rd century AD and the records of Fa-Hien, the Chinese monk, who travelled in Sri Lanka and lived for three years in the 5^th Century AD, there had been bands of occasional sea traders in the island and finally settled down.

The most well-known and systematically narrated legend is found in the Mahawamsa, the ancient chronicle that originated in the 5^th century AD. According to the chronicle, Vijaya and his followers of 700 people are recognized as the foundation of Sinhalese in the country.

According to Prof. S Paranawithana, the original home of Sinhalese was the upper Indus Valley. The same theory was put forward by Hsuan-Tsung, a Chinese traveller who visited India in the 7th century AD. The Sinhapura from which Wijaya and his follower set sail, according to Chinese travellers, was on the River Indus, and the city was located about 117 miles in the southeast direction from Taxila.

The location of the original Sinhalese in this region is supported by many archaeological findings and chronicles such as kharosthi and Lorian Tangai inscriptions. The first inscription mentions a Stupa that was built covering the large surface in honour of all Buddhists. It was built by two brothers namely Sihila and Simharaksita.

After the union of Vijaya and his 700 followers with 700 brides and their retinue of one thousand families from Madurai, the capital of the Pandya kingdom, the third wave of migrants, settled on the island.

The early settlements in ancient Sri Lanka flourished in areas with water resources such as rivers, tanks and lakes. The early settlers of Sri Lanka had chosen these areas in the dry zone due to the importance of water for agriculture. They came from the areas in India where agriculture had been the main lively good.

Advanced Irrigation System

These settlements were mainly found in the north-central dry zone of Sri Lanka, which was a vast and variegated expanse of land, as it is today, where the yearly rainfall is very limited. As the name suggests (dry-zone), however, it happened to be incredibly dry. The ancient settlers had a huge task not only to survive but also to conquer almost all of their then-known world.

The early settlers had invented a sophisticated water management system crisscrossing the entire dry zone. The tanks, canals, and sluices of the system show the very advanced principles and techniques that are second to none even today.

To find clean and pure water in a desert-like environment and unforgiving landscape, and make lush vistas in (literally) the middle of nowhere, might have seemed an impossible undertaking. However, ancient engineers of Sri Lanka found an effective and sustainable solution to eliminate the scarcity of water by implementing an ingenious irrigation system that comprised of lakes, tanks and canals. Dating back to 3000-odd years, this irrigation system proved to be very successful in meeting the requirement of water for agriculture and other requirements.

The ancient engineers built many thousands of tanks of varying sizes (from small to huge tanks that can bag a few football fields) and these tanks stored the excessive water during the heavy rain, which occurs over a few months. Labyrinthine of canals connected all corners of the dry zone with the lakes and tanks while taking the water from one place to the other. This irrigation system is a testament to the ingenuity of the ancient Sri Lankans.

An irrigation system that existed in ancient Iran (around 3000 BC), known as qanat shows some similarities to the Sri Lankan ancient irrigation system. However, Iranian ancient engineers had not invented tanks and sluices and they had only an underground canal system to take water from one place to the other. Ancient Iranians relied on pure water coming from the mountains, later it was taken to lower altitude areas. In the Sri Lankan case, the engineers had to invent a storage system by building tanks to collect water during the rainy season.

In the Sri Lankan dry zone the tanks, paddy fields, and settlements (where the water was directed) are at the same elevation as the sea level, which made it very difficult to direct water from tanks to the agricultural lands and settlements. However, the engineers of Sri Lanka built canals with meagre slopes, and some of them like “Yoda Ela” or Giant canal had only a gradient of 10 to 20 cm per kilometre, which still baffles experts today for its minute precision.

The complex and sophisticated water management system was well worth the effort, however. These Canals and tanks have allowed Sri Lankans for millennia to access and transport water in some of Sri Lanka’s most arid regions. One of the most impressive examples is in the north-central region of Sri Lanka, better known as “Raja rata” or Kings country. Here the city of Anuradhapura was built by Sri Lankan kings (10th AD – 300 BC) in a hot, dry and dusty plain, which flourished as the first capital of Sri Lanka for more than 1000 years. This dry region was not exactly endowed with nature’s bounty. Yet by way of the sophisticated irrigation system, Anuradhapura became the centre of Buddhism that stretched to all corners of the world and was regarded as one of the cities that with the most advanced civilizations in the world, famed for its opulent palaces and exquisite gardens.

The ancient irrigation system of Sri Lanka was not only for physical sustenance; it also served a spiritual purpose. Despite the harsh dry weather conditions, through irrigation, the ancient Sinhalese were able to construct the renowned, UNESCO-listed Sigiriya rock fortress, Anuradhapura city, Polonnaruwa and many such places.

Sigiriya rock fortress was a sophisticated and well-planned city dating back to the 5^th century AD. Heavenly to behold and enjoy- in stark contrast to the parched surrounding – this lush oasis, arranged with gardens, swimming pools, fountains, caves, palaces, watch-houses, moats and huge walls-an it was replete with trees, plants, veins, grasslands and waterways- everything was carefully planned in harmony and symmetry to reflect the Sinhalese adoration of nature and elements.

Anicut, Spillway, Bisokotuwa feats of ancient engineer

Sri Lanka is the country that had the most advanced early irrigation systems in Asia. The first settlers of Sri Lanka (Indo-Aryan) possessed high technical ability, with wide vision and a highly developed “water” and topographical sense.

The vastness of conception of Ceylon’s ancient irrigation system removes all doubt that the old engineer must have depended to a critical degree on a system of levelling and horizontal measurement to render the construction practicable. Anicut, spillways and Bisokotuwa are several genius constructions of ancient engineers that worth mentioning here.

Tekkan the modern Anicut

In the Anicut (tekkam) built about thirteen hundred years earlier across the Malwatu Oya to divert water to the Giant tank and in other similar contemporary structures, cement seems to have been used. It has been proved by analytics results published in the Chemical Trade Journal that this concrete prepared and used in ancient Sri Lanka 13 centuries ago, if not earlier, showed very superior properties to the Roman mortar, which had long been accepted as the best ancient product.

The Vaan or modern spillways

The spillways, some of them man-made and called vaan in Sinhalese, other natural rock called gal-vaan, over which the waters of the tank pass when surcharged by rain in flood time, range from simple contrivances in the small tank, to complex examples which must surely have an involved study of the movement of water over many years, and considerable labour to build. Two or even more spillways were sometimes provided in the larger tanks.

One of the most spectacular examples of spillways is the ancient spill-wall of chiselled granite at Kala-wewa or Kala lake, it is a stupendous construction, approximately 216 feet wide and 170 feet long, completed about the 5th century AD. The work impressively testifies to the craft of the stonemason. Each block of granite is meticulously fashioned to fit its neighbour and the whole is a wonderful monument of patient workmanship.

The Bisokotuwa or modern valve-pit

Another construction that shows a thorough knowledge of construction principal is the device known as sluice in English, and Sorowwa in Sinhala, whereby the water from the tank was led to a system of major and minor channels to be carried to fields near or far.

In the smaller tanks, where pressure was by no means great, this was achieved by means of cylindrical burnt-clay pipes laid under the bund. What permitted the old-time engineer to proceed boldly with the construction of better and bigger reservoirs was a structure found in tanks built earlier but perfected by the 3^rd century AD, known as the bisokotuwa, meaning:” the enclosure where the water level lowers.”

This outlet work built into the upstream face of the bund regulates or totally stopped the flow of the water into the discharge culverts, and also served as a silt trap. Engineers only surmise that the gates of this structure were of timber and that elephants furnished the motive power to lift them.

What is especially interesting is that even some of the earliest sluices are furnished with these triumphs of ingenuity which proves that the early engineers had mastered the problem so successfully that all others were content to copy their example. Thus, the builder of those Bisokotuwa has established a claim, which is 2,000 years old, to be considered the inventor of modern valve pits and valve towers.

Ingenious irrigation work of Sora Bora Wewa

Sora Bora Wewa or Sora Bora Lake is a classic example of the advanced engineering knowledge of ancient engineers. Especially the sluice of the lake is considered to be followed advanced engineering principles. The base of the sluice is made of a natural rock. This gigantic man-made lake is situated in the district of Mahiyangana.

The lake was constructed under the reign of King Dutugemunu in the 1^st Century BC. It is believed that the lake was constructed, while the young king was organizing his army in Mahiyangana. According to historical information the waters of Loggal Oya, Ma Oya, Diyaban Oya and Dambaruwa Wewa were directed to the Sora Bora Wewa.

The lake is situated around 1.5 kilometres from the city of Mahiyangana. It is located on the Mahiyangana-Batalayaya main road. According to the folk tales the lake was constructed by the soldier, who provided the Bulath or betel leaves to the king. Since the betel leaves are called “Bulath”, the soldier was named “Bulatha” denoting one who delivers the betel leaves.

The amount of water that can be stored in the lake is 16.89 Sq. miles and it is located well over 300 meters above sea level. The water surface of the tank exceeds 14400 acres at the maximum capacity; its dam is 1590 feet long and 20 feet wide while the height of the dam is measured to be 27.6 feet. Even today 3000 acres of land are irrigated using the waters of Sora Bora Wewa.

Bisokotuwas was an important part of the ancient tanks, which served as the sluice. Even though Sora Bora Wewa is also an ancient tank, Sora Bora Wewa is not constructed with a Bisokotuwa.

A construction similar to Bisokotuwa is constructed using granite, to control the outward water flow. The engineers opine that the ancient engineers had been able to simplify the control of outward water flow, compared to the sluice, with the invention at Sora Bora Wewa.

According to the folk stories a giant called Bulatha used to visit Mahiyangana in order to collect the Betel left required by the king. On such occasion, he had come across the region called Gonagala, where he decided to build a lake to store water.

It is believed he has dislodged a mountain and large rocks to construct the lake. Today Sora Bora Wewa serves as important water storage for the people in the region. Recently the dam of the lake was reconstructed at the cost of 4.9 million rupees.

Development of settlements in Ancient Sri Lanka

The most important factor in selecting the places for early settlements had been the water. One of the oldest settlements on the island Thambapanni originated at the banks of Aruvu Aru. Anuradha grama evolved around Malwatu Oya, Upatissa Grama flourished based on Kandara Oya whiles the Uruwela sprang at the mouth of Kala Oya. The settlers in Vijitha Nagar had chosen Mahaweli Ganga as their main source of water.

Digavapi was founded at the banks of Galoya, Maha Gama at the bank of Kirindi Oya, Kalyaniya at the banks of Kelani Ganga and the ancient settlement in southern Sri Lanka was founded at the mouth of Menik Ganga.

As the population in Sri Lanka increased the early settler spread into the deeper parts of the country. They gradually spread into the areas such as low country wet zone, Kandy, Teldeniya, Gampola, and Matale. In this manner, the settlement that originated in the dry zone had spread into the areas of the wet zone.

Population in ancient Sri Lanka

Even though the exact population of ancient Sri Lanka is not known, several historians have assumed the population by studying historical sources such as chronicles, inscriptions and books. Tenants, Johnston, Denham, Primham, Pobus, Arunachalam and Surkar are some of the historians who suggested the population in ancient Sri Lanka. It is believed that the population in the dry zone had been around 4.17 million while the population in the wet zone is around 2.19 million.

The downfall of the ancient Sri Lanka civilization

Gigantic irrigation systems, colossal palaces and Buddhist temples probably required a huge workforce in the past. Based on that historians believe that there had a sizable population in Sri Lanka.

In the later period, the sizable population of Sri Lanka was largely reduced due to the south Indian invasions. Destructing of the irrigation system and war reduced the agricultural production of the country. The malaria epidemic was another considerable factor in the destruction of ancient civilization in Sri Lanka.

The Story of Three City Tanks

Basawakkulam, Tissa wewa and Nuwara wewa (wewa means the tank), is as old as the history of Anuradhapura. It is older than the oldest historical tree in the sacred city, namely Sri Maha Bodhi. The three tanks had been used to beautify the Mahamegha, or royal pleasure garden, by filling the bathing ponds with water, providing for the communal need of the population and finally bypassing the water down to irrigate the rice fields in the suburb of Anuradhapura.

Basawakkulam lying in a shallow valley with its water held up by an earth-bound whose concave side faces upstream, claims pride of place as the oldest of the three. It has been identified as the ancient Abhayawewa, constructed by King Pandukabhaya in the 3^rd century BC. There is nothing in the structure to indicate its antiquity; it had been a remarkable achievement in the early days.

These thousands of years of the old structure remain un-breached till the modern period due to the ingenious hydraulic workmanship of the unknown engineer. It is still in very good condition even after the thrilling history of Anuradhapura, with its unique record of conquest, dynastic ambitions, regal triumphs and tragedies that had ended on the crest of a mighty wave of invasion 1200 years after the city was founded.

Tissawewa commemorates the name of King Devanampiyatissa of the 3^rd century BC. This lake lies in the southwest sector of the city and filled the picturesque lotus ponds of another ancient and very interesting foundation attributed to King Tissa – the Isurumuniya rock-temple nearby. The ancient name of the lake is unknown.

Mahawamsa ancient chronicle of Sri Lanka narrates that when the king Dutugemunu had united Lanka into one kingdom, he went to Tissawewa which was adorned according to the festival custom, to observe the traditions of a crowned king. Having disported himself in the water, the whole day, the king directed his guard to prepare to return to the palace.

The guards accordingly proceeded to pick up the symbol of sovereignty: a spear with the royal relic, which had been driven into the earth on some high ground nearby. Try as they would, they could not draw it out of the ground. Observing this miracle, Dutugemunu forthwith directed that a monument is built on the spot.

This monument enclosing the spear, is the Mirisaweti dagoba, originally 120 cubits high, and sighted within hailing distance of Tissawewa. It’s relic-chamber, altars and carvings, and the foundation of stone buildings raised off paved court-yards are witnesses to the written story, and to the antiquity of the shrine as well as the lake to which it is linked.

Nuwarawewa occupies a flat valley off the right bank of the Malwatu Oya and is not actually in the City as its name implies. There is a tradition that the water was conducted from it by means of an aqueduct across the Malwatu Oya.

In all probability, it was in the early 1^st century BC that the construction of Nuwarawewa was started. Thereafter, the city was overrun by Cholan invaders.

It was apparently when King Vatta Gamini regained his throne that the work was completed. The only clue to the age of the tank is the size of the bricks used in building the sluices. They agree closely with the bricks laid in the Abhayagiri Dagoba of Anuradhapura, which was built in the last three years of the reign of Vatta Gamini, or Valagambahu as he is sometimes called. The conclusion drawn is that the tank was completed about the year 2^nd century BC.

The Nagagala or sculptured stones depicting the seven-headed cobra, found near the ancient sluices, are symbolical of the sacred guardianship of the waters. Similar carved stones are often found in places by the sluices of tanks as well.